Regional Proteus syndrome and somatic mosaicism.

We report on a patient with regional manifestations of Proteus syndrome. Major findings included multiple hyperostoses of the calvaria, facial bones, and mandible. Additionally, the patient had a scleral tumor. This lends further support to the hypothesis of somatic mosaicism as a cause of Proteus syndrome. Because mosaic distribution of lesions is variable in extent, criteria for the diagnosis of Proteus syndrome should be loose rather than overly rigid even though patients with limited regional involvement may be particularly difficult to diagnose.